Interfaces

Systems

Various

AOR AR8000 (AOR8000)

To add a discriminator output to the AOR AR8000 (AOR8000),
you have to disassemble the middle circuit board of the scanner.
This is not too difficult.

Open the scanner by removing the two screws in the
battery compartiment and the two small screws on the side. If you
open the scanner, you look at the top of the middle
PCB.

The discriminator IC is on the bottom side. To
disassemble the board, remove the two screws at the bottom end of
the PCB. Remove the volume, squelch and dial knobs and loosen the
washers with a pair of fine tip pliers. Now you can take apart
the PCB. Be careful not to bend the two pins of the battery
connectors.

The AOR AR8000

The discriminator IC at the disassembled PCB

Close-up of the discriminator connection

The discriminator output is made on pin 11 of the
discriminator-IC, a 10489. One lead of a 'safety resistor' of 10 k
(the exact value is not critical, I use values between 5,6 and 15
k) is bent to follow the IC's pin exactly. Then, the resistor is
connected to pin 11 of the IC using a fine tip soldering iron and a
minimum amount of solder. The resistor is fixed to the IC with a
drop of glue from a glue gun. This prevents damage to the IC pin
when inadvertedly mechanical stress is applied to the
resistor.

To the other side of the resistor, I connected a small
piece of insulated wire, which leads to the 3.5 mm chassis
terminal. It's not very long, and runs between two PCB's, so it's
not necessary to use shielded cable.

I mounted the 3.5 mm chassis terminal in the other part
of the scanner. The terminal's ground lug is connected directly
to the PCB's ground. You have to scratch a bit of the protective
coating off before soldering.